from math import gcd
from decimal import Decimal

a,b,x,y = map(int,input().split())

g = gcd(a,b)
a //= g
b //= g

a = Decimal(a)
b = Decimal(b)
x = Decimal(x)
y = Decimal(y)

c = x/a
d = y/b

e = min(c,d)

ans = (a+b)*e
print(ans)